Your Very Own (Mini) Car Factory

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Your Very Own (Mini) Car Factory

It’s a blast to make things out of Lego, like castles, cars and robots. Well, as we see in this video, someone built a Lego robot that builds Lego cars itself! The robot factory grabs the body of the car, then grabs a steering wheel and presses it on. Then it sticks on the front hood, the back seat, and other bricks. In the end, out pops a car that looks exactly like the last 8-10 cars made. It takes a minute or more to stick on each piece, so you could build a car much faster than the robot. But if it’s bedtime and you need 100 cars made by tomorrow, this robot could do the job for you.

Wee ones: If the Lego car starts with 4 wheels and a floor, how many pieces does the car have?

Little kids: If every car needs 2 pairs of wheels, how many pairs do 3 cars use in total? Bonus: If you have 10 pairs in stock, how many cars can you make?

Big kids: If right now the robot makes 1 car every 30 minutes, how fast would it make a car if it made them twice as fast? Bonus: At the new speed, how many can it crank out in 1 hour? (Reminder if needed: An hour has 60 minutes.)

The sky’s the limit: Without multiplying it all out, can you tell who will finish first: a robot building 28 cars spending 6 minutes on each, or a robot building 50 cars spending 3 minutes on each?

Answers:Wee ones: 5 pieces.

Little kids: 6 pairs of wheels. Bonus: 5 cars.

Big kids: 1 every 15 minutes. Bonus: 4 cars per hour.

The sky’s the limit: The 2nd robot will finish first. It’s making fewer than double the cars, but at exactly twice the speed. If you did multiply it all out, you’d get 28 x 6 = 168 minutes for the 1st robot, and 50 x 3 = 150 minutes for the 2nd.

About the Author

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.